East Turkistan is rich in natural resources.
Despite its inland climate and bitter natural environment, there are plenty of agricultural products. Agricultural lands are fertile with snowmelt from the alps and it is famous with the variety and quality of the fruits and it is often called "Land of Fruit". Using the extensive grassland also provide rich animal products.
Apart from the livestock and cultivated plants, they are also rich in wild animals and wild plants. There are 580 different wild animal species and more than 3,000 plant species.
As for the mineral resources, they have metals and jewels such as uranium, platinum, gold, diamond, ruby and emerald. They also have iron, lead, copper, silver, sulfur, tin and mica. They have rich energy resources like coal, oil and gas. It is estimated that the amount of the coal there are quarter of the entire China's and the amount of oil and gas there are 1/3 of the entire China's.
Tarim Basin is the biggest sedimentary basin in China and there are possibilities that there are more resources there as it has not been explored entirely. The Karamay oil field in western Dzungaria has been developed for a long time and its amount of oil producing is 4th biggest in China. Other oil fields in China have been reducing the production and oil fields in East Turkistan are being more important to China.
One of the reason China never want to let the land go is the rich natural resources.
Though there are plenty of natural resources in their land, the Hans are dominating them and take that to Central. East Turkistan people's resentment for this is large.
Between the Great Leap Forward and Cultural Revolution, Socialism was introduced to East Turkistan, that is to say economic integration was forced in East Turkistan. The land owned by East Turkistani were taken and agriculture was carried on collectively and industries were nationalized.
Xinjiang Production and Construction Corps took a big part that time. It was mainly composed with retired military of People's Liberation Army that invaded East Turkistan and most of them were Hans. Xinjiang Production and Construction Corps was an organization that Communist Party, army and the enterprises united. They were given the responsibility of developing the land and security of the boarder. With the reins of power, Xinjiang Production and Construction Corps built wealth by dominating the most fertile agricultural and pasture land and water resource. They are the one who suppress East Turkistani saying that is separatist movement when they express dissent about the domineeringness of the Hans. Xinjiang Production and Construction Corps has 2.5 million soldiers and they show off their military power for the contingency and maintaining the enormous economic force.

If resource and land grab was the first economic integration, market economy and Han people's hegira after the Economic reform in the People's Republic of China would be the second economic integration.
By giving preferential treatment to Hans who migrate to East Turkistan supported by Economic reform in the People's Republic of China and China Western Development, the number of Han migrants are increasing drastically up until now.
The Hans lived in northern part of East Turkistan (Tian Shan and north), where the oilfield was developed, the precipitation rate was quite high and the land was productive. Though there were some Hans in the south, they mainly stayed in the newly industrializing cities. But now, with the progress of the market economy, the Hans are spreading themselves in south and remote region.
Even in Kashgar, called 'Land of Uyghur', the life and culture of Uyghurs are being destroyed by the hegira of Hans. Cityscape of the Silkroad is also being changed into a totally different style. Since the opening of Southern Xinjiang Railway in 1999 that runs between Korla and Kashgar, economical and cultural integration has been intensified.